I'm building ICL 7107 digital voltmeter with 200mV full scale as Figure 12 (page 11) on http://www.intersil.com/data/fn/fn3082.pdf
Here is the problem I'm facing:
it shows random numbers, sometimes showing 1666, and it has no effects even when I try to calibrate by adjusting the potentiometer or shorting the inputs pins the values remain the same. Even the whole potentiometer is removed the value still stay there!
I have read through the datasheet and couldn't find any possible defects of the components that might have caused this.
I have tried to replace the 0.1 microfarad capacitor with 1 microfarad but the problem remains the same and I did check the connection trace.
So, I was wondering if you have any idea? and Thanks in advance, that really means a lot to me.